Northstar Engines and System Technical Discussion Discussion, cracked block issue, common?? in Cadillac Engine Technical Discussion; I have a 2000 Deville that I was doing the all too common HG replacement and after everything was put ...

cracked block issue, common??

I have a 2000 Deville that I was doing the all too common HG replacement and after everything was put together I noticed that the block was cracked. The crack was near the bottom of the outer bolt holes and went the entire length of the block. I found another block the same year and looked at this one and it also had the same crack. Was this a common thing for 2000? What other years of blocks can I use? Can I use an older block or what are the issues with doing that or is that a bad choice? I need some help/advice, 2 blocks and still looking. Thanks

Re: cracked block issue, common??

Ewill - there's a car I just did the HG's on that I believe has an experimental engine in. The grooves in the block for the half-case seals are chamfered on a 45 degree angle- I've never seen this before- have you? I'm used to these grooves being straight like this : |_| and not like \_/. There are some other wierd differences.

My 2004 GXP - the half-case seal grooves don't even reach the rear main seal. They leave a gap where oil can seep out. Poor modification if you ask me. Thank goodness for good RTV sealant.

Re: cracked block issue, common??

Thanks 97, I may be calling you, I found 1 more core that I am picking up tonight. This is number 3 so hopefully it's a charm.

I do have a good question though. I will be putting insets into the block. Since the inserts are locked in can I use oil on the bolts or do they still need loctite as well? Just wondering what others thought on this, not trying to bring up an insert debate.

Also would anyone feel comfortable using bolts over that were torqued and never ran, I had the heads torqued on and that afternoon the block cracked, I took the bolts out the next day. Just looking for opinions/experience. Thanks

Re: cracked block issue, common??

I believe you are not supposed to reuse the bolts. They come from the factory with some type of thread locker on them, but see what others say. Not sure if that holds true in your case or not, but DO NOT put oil on them. That will through the torque settings way off.

Re: cracked block issue, common??

97, I don't do much engine work these days. My hands are wearing out from years of abuse, we have a dedicated department to handle these issues.
I hadn't seen the groove but I wouldn't be surprised if they changed it.
I would have to check but I am not sure they even use the slip in seals anymore, I think they just put RTV in there nowadays.
Don't take my word for it though.

I know our guys use new bolts, not sure if it is a threadlocker issue or a torque to yield issue...I am not really well versed in HG servicing for the reasons I mentioned above.

Re: cracked block issue, common??

I don't blame you Ewill. When I was really really busy - working 5am-11pm (I kid you not) my hands had to have a few days off once in a while. These Northstars have a lot of sharp aluminum edges too, some like a razor.

The seals were still used in my '04- that's the newest one I've worked on. I can tell you one thing- I will never regret switching to the GM RTV sealant. That's the best stuff I've ever used. I still use rubber seals in the oil pans, but follow that with a bead of RTV. When I tore down a warranty engine today, that little bit of RTV around the outside of the oil pan seal held it down like crazy clue- I had to carefully pry the pan off. Shoot I don't even need bolts anymore I'll never use any other RTV sealant again as long as ACDelco sells this stuff.

onestout - if it doesn't work out with that other block, I'll sell you a block (upper and lower) for $900 shipped (UPS ground). Since the threads will be new and installing inserts would be a "very bad idea" IMO, I would go with new bolts and forget about inserts. Sorry but I'm not going to give you advice that I feel may result in failed head gasket sealing. Either new bolts and original factory threads (new block only) or studs, nuts, and washers. I'm sorry if you didn't want to hear that but I will always say this, nobody wants to do the job the 2nd time around.

To date I've had to remove two engines that I had already had out and re-installed. One was for a nick in a cylinder head that I had missed and another was a camshaft that jumped out of position. Oh- and I have to rebuild a 2nd engine for a customer who's engine had been run dry. Of these instances one was almost entirely my fault (so I fixed that at no cost), the second could have been avoided if the customer had taken my advice, so I charged him parts only, and the third, appears to be a lack of oil. I still hold over a 99% success rate. I consider this very good, but even still, doing something the second time around is simply no fun. I don't want this to happen to anyone. Do it once, do it right, and be done with it. I'm learning with my mistakes and if I can help anyone with my experiences, I will be more than happy to pass that info on. I'm learning a lot from these forums and its members as well.

Re: cracked block issue, common??

The only complaints I hear from heavy duty are when they do timeserts and an extended warranty company will only pay for the ones that are stripped instead of doing them all.
Without fail (or perhaps with fail) when they install the heads more of them start to strip.
Again, sorry I don't know the details.

Years ago I used my fists as hammers to install hubcaps, and I'd snap tissue in my wrists because I was too stupid to walk to my toolbox to get an oil filter wrench.
Now I am paying the price. I use air tools or electric tools for all the mechanical work I do because of the wear and tear and I try to stick to things more electrical and diagnostic oriented. I do OnStar and entertainment systems for the most part, and I back that up with pretty much anything needed on the CTS-V's that come in and all the XLR work you'd think a guy could handle. Not sure how many more of those gas tanks I can take out though, it's tough work.
I spend most of my time staring at my computer looking for electrical issues in the schematics actually.
... but I digress.

If I get a chance I'll ask some of the questions that I see brought up here and see if I can get some answers.